The purpose of this study is to describe the range and incidence of symptoms, treatments, and
complications related to pyruvate kinase deficiency (PKD). Eligible patients are those of all
ages with known PKD or with a hemolytic anemia and a family member with PKD. The study will
collect retrospective medical history, routine clinical care data, and quality of life
measures at baseline and annually for patients with PKD.

Stanford is currently not accepting patients for this trial.For more information, please contact Heather Hilmoe, CRA, 650-725-1662.

Abstract

Forkhead box M1 (FOXM1) belongs to the forkhead/winged-helix family of transcription factors and regulates a network of proliferation-associated genes. Its abnormal upregulation has been shown to be a key driver of cancer progression and an initiating factor in oncogenesis. FOXM1 is also highly expressed in stem/progenitor cells and inhibits their differentiation, suggesting that FOXM1 plays a role in the maintenance of multipotency. However, the exact molecular mechanisms by which FOXM1 regulates human stem/progenitor cells are still uncharacterized. To understand the role of FOXM1 in normal hematopoiesis, human cord blood CD34(+) cells were transduced with FOXM1 short hairpin ribonucleic acid (shRNA) lentivirus. Knockdown of FOXM1 resulted in a 2-fold increase in erythroid cells compared to myeloid cells. Additionally, knockdown of FOXM1 increased bromodeoxyuridine (BrdU) incorporation in erythroid cells, suggesting greater proliferation of erythroid progenitors. We also observed that the defective phosphorylation of FOXM1 by checkpoint kinase 2 (CHK2) or cyclin-dependent kinases 1/2 (CDK1/2) increased the erythroid population in a manner similar to knockdown of FOXM1. Finally, we found that an inhibitor of FOXM1, forkhead domain inhibitor-6 (FDI-6), increased red blood cell numbers through increased proliferation of erythroid precursors. Overall, our data suggest a novel function of FOXM1 in normal human hematopoiesis.

Abstract

Central venous access devices (CVADs) are used in the care of paediatric haemophilic patients with difficult peripheral access, but their use is limited by complications such as infection. We previously published our experience with monthly recombinant tissue plasminogen activator (r-tPA) administration to CVADs of haemophilic patients as an intervention for infection prophylaxis, which suggested a 10-fold decrease in infection rate compared to published rates without r-tPA.This study was conducted to assess the CVAD infection rate in an expanded haemophilia cohort receiving r-tPA over an extended period.A retrospective review was performed on patients with haemophilia who received monthly r-tPA to CVADs, with data collected from January 1, 2008 to December 31, 2012. The data were merged with the previously reported data set (collected from June 1, 1998 to December 31, 2007).Over the entire observation period, there were 46 350 CVAD days among 32 patients [26 severe factor VIII (FVIII) deficiency, six severe FIX deficiency]. Eight patients received immune tolerance therapy for inhibitors and 24 patients received prophylactic factor administration. No patients were HIV positive. Three infections were observed, with an overall infection rate of 0.06 infections per 1000 CVAD days.A low CVAD infection rate, similar to that observed in our previous study (0.04 per 1000 CVAD days), was observed in this expanded haemophilia cohort treated with prophylactic r-tPA, supporting the use of monthly r-tPA as CVAD infection prophylaxis in haemophilia patients.

Abstract

Diamond-Blackfan anemia (DBA) is an inherited disorder characterized by defects in erythropoiesis, congenital abnormalities, and predisposition to cancer. Approximately 25% of DBA patients have a mutation in RPS19, which encodes a component of the 40S ribosomal subunit. Upregulation of p53 contributes to the pathogenesis of DBA, but the link between ribosomal protein mutations and erythropoietic defects is not well understood. We found that RPS19 deficiency in hematopoietic progenitor cells leads to decreased GATA1 expression in the erythroid progenitor population and p53-dependent upregulation of tumor necrosis factor-? (TNF-?) in nonerythroid cells. The decrease in GATA1 expression was mediated, at least in part, by activation of p38 MAPK in erythroid cells and rescued by inhibition of TNF-? or p53. The anemia phenotype in rps19-deficient zebrafish was reversed by treatment with the TNF-? inhibitor etanercept. Our data reveal that RPS19 deficiency leads to inflammation, p53-dependent increase in TNF-?, activation of p38 MAPK, and decreased GATA1 expression, suggesting a novel mechanism for the erythroid defects observed in DBA.

Abstract

In the majority of children with ALF, the etiology is unknown and liver transplantation is often needed for survival. A patient case prompted us to consider that immune dysregulation may be the cause of indeterminate acute hepatitis and liver failure in children. Our study includes nine pediatric patients treated under a multidisciplinary clinical protocol to identify and treat immune-mediated acute liver injury. Patients with evidence of inflammation and no active infection on biopsy received treatment with intravenous immune globulin and methylprednisolone. Seven patients had at least one positive immune marker before or after treatment. All patients had a CD8+ T-cell predominant liver injury that completely or partially responded to immune therapy. Five of the nine patients recovered liver function and did not require liver transplantation. Three of these patients subsequently developed bone marrow failure and were treated with either immunosuppression or stem cell transplant. This series highlights the importance of this tissue-based approach to diagnosis and treatment that may improve transplant-free survival. Further research is necessary to better characterize the immune injury and to predict the subset of patients at risk for bone marrow failure who may benefit from earlier and stronger immunosuppressive therapy.

Abstract

Ribosomal biogenesis involves the processing of pre-ribosomal RNA. A deficiency of some ribosomal proteins (RPs) impairs processing and causes Diamond Blackfan anemia (DBA), which is associated with anemia, congenital malformations and cancer. p53 mediates many features of DBA, but the mechanism of p53 activation remains unclear. Another hallmark of DBA is the upregulation of adenosine deaminase (ADA), indicating changes in nucleotide metabolism. In RP-deficient zebrafish, we found activation of both nucleotide catabolism and biosynthesis, which is consistent with the need to break and replace the faulty ribosomal RNA. We also found upregulation of deoxynucleotide triphosphate (dNTP) synthesis - a typical response to replication stress and DNA damage. Both RP-deficient zebrafish and human hematopoietic cells showed activation of the ATR/ATM-CHK1/CHK2/p53 pathway. Other features of RP deficiency included an imbalanced dNTP pool, ATP depletion and AMPK activation. Replication stress and DNA damage in cultured cells in non-DBA models can be decreased by exogenous nucleosides. Therefore, we treated RP-deficient zebrafish embryos with exogenous nucleosides and observed decreased activation of p53 and AMPK, reduced apoptosis, and rescue of hematopoiesis. Our data suggest that the DNA damage response contributes to p53 activation in cellular and zebrafish models of DBA. Furthermore, the rescue of RP-deficient zebrafish with exogenous nucleosides suggests that nucleoside supplements could be beneficial in the treatment of DBA.

Abstract

Diamond-Blackfan anemia (DBA) is an inherited red blood cell aplasia that usually presents during the first year of life. The main features of the disease are normochromic and macrocytic anemia, reticulocytopenia, and nearly absent erythroid progenitors in the bone marrow. The patients also present with growth retardation and craniofacial, upper limb, heart and urinary system congenital malformations in ~30-50 % of cases. The disease has been associated with point mutations and large deletions in ten ribosomal protein (RP) genes RPS19, RPS24, RPS17, RPL35A, RPL5, RPL11, RPS7, RPS10, RPS26, and RPL26 and GATA1 in about 60-65 % of patients. Here, we report a novel large deletion in RPL15, a gene not previously implicated to be causative in DBA. Like RPL26, RPL15 presents the distinctive feature of being required both for 60S subunit formation and for efficient cleavage of the internal transcribed spacer 1. In addition, we detected five deletions in RP genes in which mutations have been previously shown to cause DBA: one each in RPS19, RPS24, and RPS26, and two in RPS17. Pre-ribosomal RNA processing was affected in cells established from the patients bearing these deletions, suggesting a possible molecular basis for their pathological effect. These data identify RPL15 as a new gene involved in DBA and further support the presence of large deletions in RP genes in DBA patients.

Abstract

Immune thrombocytopenia (ITP) in children less than one year of age is less well characterized compared to ITP in toddlers and school-age children. We performed a 10-year retrospective review of ITP patients in this age-cohort at our institution. Diagnosis and classification were made according to the 2009 International Working Group criteria. Fourteen infants were identified. Their bleeding scores were Grades 1 to 2 (79%), Grade 3 (22%), Grades 4 to 5 (0%). Eight patients received treatment with a 75% response rate. Three patients (21%) developed chronic ITP. These observations suggest that ITP in very young patients is similar to typical childhood ITP.

Abstract

Autosomal dominant dehydrated hereditary stomatocytosis (DHSt) usually presents as a compensated hemolytic anemia with macrocytosis and abnormally shaped red blood cells (RBCs). DHSt is part of a pleiotropic syndrome that may also exhibit pseudohyperkalemia and perinatal edema. We identified PIEZO1 as the disease gene for pleiotropic DHSt in a large kindred by exome sequencing analysis within the previously mapped 16q23-q24 interval. In 26 affected individuals among 7 multigenerational DHSt families with the pleiotropic syndrome, 11 heterozygous PIEZO1 missense mutations cosegregated with disease. PIEZO1 is expressed in the plasma membranes of RBCs and its messenger RNA, and protein levels increase during in vitro erythroid differentiation of CD34(+) cells. PIEZO1 is also expressed in liver and bone marrow during human and mouse development. We suggest for the first time a correlation between a PIEZO1 mutation and perinatal edema. DHSt patient red cells with the R2456H mutation exhibit increased ion-channel activity. Functional studies of PIEZO1 mutant R2488Q expressed in Xenopus oocytes demonstrated changes in ion-channel activity consistent with the altered cation content of DHSt patient red cells. Our findings provide direct evidence that R2456H and R2488Q mutations in PIEZO1 alter mechanosensitive channel regulation, leading to increased cation transport in erythroid cells.

Abstract

Diamond-Blackfan anaemia (DBA) is an inherited bone marrow failure syndrome (IBMFS) characterized by red cell aplasia. Mutations in ribosomal genes are found in more than 50% of cases. Elevated erythrocyte adenosine deaminase (eADA) was first noted in DBA in 1983. In this study we determined the value of eADA for the diagnosis of DBA compared with other IBMFS; the association of eADA in DBA with age, gender or other haematological parameters; and the association with known DBA-related gene mutations. For the diagnosis of DBA compared with non-DBA patients with other bone marrow failure syndromes, eADA had a sensitivity of 84%, specificity 95%, and positive and negative predictive values of 91%. In patients with DBA there was no association between eADA and gender, age, or other haematological parameters. Erythrocyte ADA segregated with, as well as independent of, known DBA gene mutations. While eADA was an excellent confirmatory test for DBA, 16% of patients with classical clinical DBA had a normal eADA.

Abstract

Diamond-Blackfan anemia (DBA) is an inherited form of pure red cell aplasia that usually presents in infancy or early childhood and is associated with congenital malformations in ?30-50% of patients. DBA has been associated with mutations in nine ribosomal protein (RP) genes in about 53% of patients. We completed a large-scale screen of 79 RP genes by sequencing 16 RP genes (RPL3, RPL7, RPL8, RPL10, RPL14, RPL17, RPL19, RPL23A, RPL26, RPL27, RPL35, RPL36A, RPL39, RPS4X, RPS4Y1, and RPS21) in 96 DBA probands. We identified a de novo two-nucleotide deletion in RPL26 in one proband associated with multiple severe physical abnormalities. This mutation gives rise to a remarkable ribosome biogenesis defect that affects maturation of both the small and the large subunits. We also found a deletion in RPL19 and missense mutations in RPL3 and RPL23A, which may be variants of unknown significance. Together with RPL5, RPL11, and RPS7, RPL26 is the fourth RP regulating p53 activity that is linked to DBA.

Abstract

Hemophilia B, an X-linked disorder, is ideally suited for gene therapy. We investigated the use of a new gene therapy in patients with the disorder.We infused a single dose of a serotype-8-pseudotyped, self-complementary adenovirus-associated virus (AAV) vector expressing a codon-optimized human factor IX (FIX) transgene (scAAV2/8-LP1-hFIXco) in a peripheral vein in six patients with severe hemophilia B (FIX activity, <1% of normal values). Study participants were enrolled sequentially in one of three cohorts (given a high, intermediate, or low dose of vector), with two participants in each group. Vector was administered without immunosuppressive therapy, and participants were followed for 6 to 16 months.AAV-mediated expression of FIX at 2 to 11% of normal levels was observed in all participants. Four of the six discontinued FIX prophylaxis and remained free of spontaneous hemorrhage; in the other two, the interval between prophylactic injections was increased. Of the two participants who received the high dose of vector, one had a transient, asymptomatic elevation of serum aminotransferase levels, which was associated with the detection of AAV8-capsid-specific T cells in the peripheral blood; the other had a slight increase in liver-enzyme levels, the cause of which was less clear. Each of these two participants received a short course of glucocorticoid therapy, which rapidly normalized aminotransferase levels and maintained FIX levels in the range of 3 to 11% of normal values.Peripheral-vein infusion of scAAV2/8-LP1-hFIXco resulted in FIX transgene expression at levels sufficient to improve the bleeding phenotype, with few side effects. Although immune-mediated clearance of AAV-transduced hepatocytes remains a concern, this process may be controlled with a short course of glucocorticoids without loss of transgene expression. (Funded by the Medical Research Council and others; ClinicalTrials.gov number, NCT00979238.).

Abstract

Reduced gene dosage of ribosomal protein subunits has been implicated in 5q- myelodysplastic syndrome and Diamond Blackfan anemia, but the cellular and pathophysiologic defects associated with these conditions are enigmatic. Using conditional inactivation of the ribosomal protein S6 gene in laboratory mice, we found that reduced ribosomal protein gene dosage recapitulates cardinal features of the 5q- syndrome, including macrocytic anemia, erythroid hypoplasia, and megakaryocytic dysplasia with thrombocytosis, and that p53 plays a critical role in manifestation of these phenotypes. The blood cell abnormalities are accompanied by a reduction in the number of HSCs, a specific defect in late erythrocyte development, and suggest a disease-specific ontogenetic pathway for megakaryocyte development. Further studies of highly purified HSCs from healthy patients and from those with myelodysplastic syndrome link reduced expression of ribosomal protein genes to decreased RBC maturation and suggest an underlying and common pathophysiologic pathway for additional subtypes of myelodysplastic syndrome.

Abstract

Bovine topical thrombin is commonly used for local hemostasis in pediatric surgery. Acquired inhibitors to coagulation factors, particularly to factor V and bovine thrombin, have been infrequently reported in the pediatric population. We report a 3-year-old male who developed a coagulopathy and clinical bleeding after cardiothoracic surgery, during which bovine topical thrombin was used for local hemostasis. Laboratory tests revealed elevated prothrombin, partial thromboplastin, and thrombin times, and a low factor V activity level. He was found to have both human-thrombin and factor V inhibitors, among the first reported cases of these combined inhibitors secondary to bovine topical thrombin. He was treated with intravenous immunoglobulin and steroids with a rapid and durable response.

Abstract

Iron deposition can occur in the kidneys as a result of hemolysis or extensive iron overload from transfusions. With T2* MRI, renal iron deposition can be visualized. In this report, renal corticomedullary junction iron deposition is noted using T2* MRI in a boy with red cell aplasia. The renal corticomedullary junction iron deposition is an indication of the severity of his iron overload. This is an unusual finding and brings clinical attention to the boy's renal function for further evaluation.

Abstract

Diamond-Blackfan anemia (DBA), an inherited bone marrow failure syndrome characterized by anemia that usually presents before the first birthday or in early childhood, is associated with birth defects and an increased risk of cancer. Although anemia is the most prominent feature of DBA, the disease is also characterized by growth retardation and congenital malformations, in particular craniofacial, upper limb, heart, and urinary system defects that are present in approximately 30%-50% of patients. DBA has been associated with mutations in seven ribosomal protein (RP) genes, RPS19, RPS24, RPS17, RPL35A, RPL5, RPL11, and RPS7, in about 43% of patients. To continue our large-scale screen of RP genes in a DBA population, we sequenced 35 ribosomal protein genes, RPL15, RPL24, RPL29, RPL32, RPL34, RPL9, RPL37, RPS14, RPS23, RPL10A, RPS10, RPS12, RPS18, RPL30, RPS20, RPL12, RPL7A, RPS6, RPL27A, RPLP2, RPS25, RPS3, RPL41, RPL6, RPLP0, RPS26, RPL21, RPL36AL, RPS29, RPL4, RPLP1, RPL13, RPS15A, RPS2, and RPL38, in our DBA patient cohort of 117 probands. We identified three distinct mutations of RPS10 in five probands and nine distinct mutations of RPS26 in 12 probands. Pre-rRNA analysis in lymphoblastoid cells from patients bearing mutations in RPS10 and RPS26 showed elevated levels of 18S-E pre-rRNA. This accumulation is consistent with the phenotype observed in HeLa cells after knockdown of RPS10 or RPS26 expression with siRNAs, which indicates that mutations in the RPS10 and RPS26 genes in DBA patients affect the function of the proteins in rRNA processing.

Abstract

Central venous access devices (CVAD) have been effectively used in the care of haemophilia patients. This is particularly true in children, who often have difficult venous access. CVAD complications (infection and thrombosis), risk factors, and complication rates, have been well-documented. However, effective interventions which decrease complication rates have not been identified. In this study, we review our experience with the use of monthly recombinant tissue plasminogen activator (rtPA) administration in haemophilia patients with fully implanted CVADs. Data on 19 haemophilia patients with 24 CVADs were available for analysis, with a total of 24 520 CVAD days. An infection rate of 0.04 infections per 1000 CVAD days and a thrombosis rate of 0.04 thrombi per 1000 CVAD days was observed. The observed infectious complication rate is at least one logarithm lower than many published CVAD infection rates in haemophilia patients who have not received rtPA administration. No bleeding complications were noted. Monthly rtPA is safe and appears to be effective in decreasing CVAD infection rates. Larger, randomized controlled studies are indicated to validate this finding.

Abstract

We previously showed in a prospective study that rituximab appears to be effective in some children and adolescents with severe chronic immune thrombocytopenia. Eleven of 36 patients achieved and maintained platelet counts over 50,000/mm(3) within the first 12 weeks. These patients were followed for the next year.Platelet counts were monitored monthly and all subsequent bleeding manifestations and need for further treatment was noted.Eight of the 11 initial responders maintained a platelet count over 150,000/mm(3) without further treatment intervention. Three patients had a late relapse. One initial non-responder achieved a remission after 16 weeks, and two additional patients maintained platelet counts around 50,000/mm(3) without the need for further intervention.Rituximab resulted in sustained efficacy with platelet counts of 50,000/mm(3) or higher in 11 of 36 patients (31%).

Abstract

Diamond-Blackfan anemia (DBA), a congenital bone-marrow-failure syndrome, is characterized by red blood cell aplasia, macrocytic anemia, clinical heterogeneity, and increased risk of malignancy. Although anemia is the most prominent feature of DBA, the disease is also characterized by growth retardation and congenital anomalies that are present in approximately 30%-50% of patients. The disease has been associated with mutations in four ribosomal protein (RP) genes, RPS19, RPS24, RPS17, and RPL35A, in about 30% of patients. However, the genetic basis of the remaining 70% of cases is still unknown. Here, we report the second known mutation in RPS17 and probable pathogenic mutations in three more RP genes, RPL5, RPL11, and RPS7. In addition, we identified rare variants of unknown significance in three other genes, RPL36, RPS15, and RPS27A. Remarkably, careful review of the clinical data showed that mutations in RPL5 are associated with multiple physical abnormalities, including craniofacial, thumb, and heart anomalies, whereas isolated thumb malformations are predominantly present in patients carrying mutations in RPL11. We also demonstrate that mutations of RPL5, RPL11, or RPS7 in DBA cells is associated with diverse defects in the maturation of ribosomal RNAs in the large or the small ribosomal subunit production pathway, expanding the repertoire of ribosomal RNA processing defects associated with DBA.

Abstract

Diamond Blackfan anaemia (DBA) is a rare, genetically and clinically heterogeneous, inherited red cell aplasia. Classical DBA affects about seven per million live births and presents during the first year of life. However, as mutated genes have been discovered in DBA, non-classical cases with less distinct phenotypes are being described in adults as well as children. In caring for these patients it is often difficult to have a clear understanding of the treatment options and their outcomes because of the lack of complete information on the natural history of the disease. The purpose of this document is to review the criteria for diagnosis, evaluate the available treatment options, including corticosteroid and transfusion therapies and stem cell transplantation, and propose a plan for optimizing patient care. Congenital anomalies, mode of inheritance, cancer predisposition, and pregnancy in DBA are also reviewed. Evidence-based conclusions will be made when possible; however, as in many rare diseases, the data are often anecdotal and the recommendations are based upon the best judgment of experienced clinicians. The recommendations regarding the diagnosis and management described in this report are the result of deliberations and discussions at an international consensus conference.

Abstract

Anemia is a common finding in post-liver transplant patients. Causes for the anemia include nutritional deficiencies, red cell aplasia as well as immune-mediated hemolysis. One of the immunologic causes of hemolytic anemia is drug-induced hemolysis. Tacrolimus is a common immunosuppressant used in post-liver transplant patients to prevent graft rejection. There have been reports of tacrolimus-associated hemolytic anemia secondary to hemolytic uremic syndrome as well as autoimmune hemolysis. There are also case-reports of severe hemolytic anemia related to cold agglutinin production in post-liver transplant patients. We described in this paper three cases of severe cold agglutinin hemolytic anemia in three pediatric liver transplant patients. Steroid therapy, plasmapheresis and withdrawal of tacrolimus led to resolution of the severe hemolytic process in each case. Whether the immune-mediated hemolysis is related to tacrolimus is not clear and needs to be characterized further.

Abstract

Diamond-Blackfan anemia (DBA) is a rare congenital red-cell aplasia characterized by anemia, bone-marrow erythroblastopenia, and congenital anomalies and is associated with heterozygous mutations in the ribosomal protein (RP) S19 gene (RPS19) in approximately 25% of probands. We report identification of de novo nonsense and splice-site mutations in another RP, RPS24 (encoded by RPS24 [10q22-q23]) in approximately 2% of RPS19 mutation-negative probands. This finding strongly suggests that DBA is a disorder of ribosome synthesis and that mutations in other RP or associated genes that lead to disrupted ribosomal biogenesis and/or function may also cause DBA.

Abstract

We have previously shown that a single portal vein infusion of a recombinant adeno-associated viral vector (rAAV) expressing canine Factor IX (F.IX) resulted in long-term expression of therapeutic levels of F.IX in dogs with severe hemophilia B. We carried out a phase 1/2 dose-escalation clinical study to extend this approach to humans with severe hemophilia B. rAAV-2 vector expressing human F.IX was infused through the hepatic artery into seven subjects. The data show that: (i) vector infusion at doses up to 2 x 10(12) vg/kg was not associated with acute or long-lasting toxicity; (ii) therapeutic levels of F.IX were achieved at the highest dose tested; (iii) duration of expression at therapeutic levels was limited to a period of approximately 8 weeks; (iv) a gradual decline in F.IX was accompanied by a transient asymptomatic elevation of liver transaminases that resolved without treatment. Further studies suggested that destruction of transduced hepatocytes by cell-mediated immunity targeting antigens of the AAV capsid caused both the decline in F.IX and the transient transaminitis. We conclude that rAAV-2 vectors can transduce human hepatocytes in vivo to result in therapeutically relevant levels of F.IX, but that future studies in humans may require immunomodulation to achieve long-term expression.

Abstract

Hemophilia B is an X-linked coagulopathy caused by absence of functional coagulation factor IX (F.IX). Previously, we established an experimental basis for gene transfer as a method of treating the disease in mice and hemophilic dogs through intramuscular injection of a recombinant adeno-associated viral (rAAV) vector expressing F.IX. In this study we investigated the safety of this approach in patients with hemophilia B. In an open-label dose-escalation study, adult men with severe hemophilia B (F.IX < 1%) due to a missense mutation were injected at multiple intramuscular sites with an rAAV vector. At doses ranging from 2 x 10(11) vector genomes (vg)/kg to 1.8 x 10(12) vg/kg, there was no evidence of local or systemic toxicity up to 40 months after injection. Muscle biopsies of injection sites performed 2 to 10 months after vector administration confirmed gene transfer as evidenced by Southern blot and transgene expression as evidenced by immunohistochemical staining. Pre-existing high-titer antibodies to AAV did not prevent gene transfer or expression. Despite strong evidence for gene transfer and expression, circulating levels of F.IX were in all cases less than 2% and most were less than 1%. Although more extensive transduction of muscle fibers will be required to develop a therapy that reliably raises circulating levels to more than 1% in all subjects, these results of the first parenteral administration of rAAV demonstrate that administration of AAV vector by the intramuscular route is safe at the doses tested and effects gene transfer and expression in humans in a manner similar to that seen in animals.

Abstract

Because bruising and bleeding are normal events of childhood, the pediatrician must be able to determine whether a child's symptoms are normal or perhaps indicative of a defective hemostasis. A thorough medical history and physical examination should enable the clinician to choose those patients warranting further evaluation. Rather than referral to a hematologist at that point in time, pediatricians should be quite capable of performing the initial laboratory evaluation and making the correct diagnosis in a majority of cases.

Abstract

To report a case of severe postinfectious autoimmune hemolytic anemia (AIHA) owing to the Donath-Landsteiner (DL) antibody resolving with plasmapheresis, and to review the pathophysiology of this underrecognized cause of pediatric AIHA and its potential susceptibility to plasmapheresis therapy.Descriptive case report.A pediatric intensive care unit in a university children's hospital.A 5-yr-old Hispanic female had gastroenteritis followed by progressive intravascular hemolysis, initially attributed to acute postinfectious cold hemagglutinin (immunoglobulin M) disease.With no slowing in the rate of hemolysis, a continued need for frequent transfusions, and a lack of response to corticosteroid and intravenous immunoglobulin therapy, a 3-day course of plasmapheresis was administered.The patient presented to an emergency department with an initial hematocrit of 22%, which fell to 12% by hospital admission. She received nine transfusions over 7 days, with her hematocrit reaching a nadir of 11% on the 5th day of hospitalization. Once plasmapheresis was initiated, she required no further transfusion. Analysis of serum from initial presentation demonstrated biphasic hemolysis, confirming the presence of the DL antibody.In AIHA, in which the direct antiglobulin test detects primarily C3 rather than immunoglobulin G, especially in children, the DL antibody must be considered. Confirming the diagnosis rapidly may be critical, especially in cases of severe hemolysis, because this may help direct therapy. A low titer of DL antibody can mediate severe intravascular hemolysis given its propensity to sensitize, detach, and rebind erythrocytes with changes in temperature in the microcirculation. However, given the transient and relatively brief production of the DL antibody in postviral illness, early clearance of the offending antibody may be possible with plasmapheresis, without the expectation for significant rebound antibody production, potentially decreasing the length of hospital stay and the need for transfusions.

Abstract

We report on maternal first cousins with bilateral microtia, micrognathia, cleft palate and hematologic findings of Diamond-Blackfan anemia (DBA). The similarity of findings shared between our cases and a female reported by Hasan and Inoue [1993] suggests that this is a distinctive syndrome, rather than a chance association. DBA is a heterogeneous disorder, caused in about 25% of cases by heterozygous mutations in the RPS19 gene (DBA1). Mutation analysis in our cases did not show an RPS19 mutation, and 2 alleles were present in each. Segregation analysis for DBA1 on chromosome 19 and DBA2 on 8p23 was not consistent with linkage. We conclude that this syndrome of microtia, cleft palate and DBA is not allelic to known DBA loci.

Abstract

Diamond-Blackfan anemia (DBA) is a rare congenital hypoplastic anemia that usually presents early in infancy and is inherited in 10% to 20% of cases. Linkage analysis has shown that DBA in many of both dominant and recessive DBA families mapped to chromosome 19q13.2 leading to the cloning of a gene on chromosome 19q13.2 that encodes a ribosomal protein, RPS19. However, subsequently, mutations of the RPS19 gene have only been identified in 25% of all patients with DBA. This study analyzed 14 multiplex DBA families, 9 of which had 19q13.2 haplotypes inconsistent with 19q linkage. A genome-wide search for linked loci suggested the presence of a second DBA locus in a 26.4-centimorgan (cM) interval on human chromosome 8p. Subsequently, 24 additional DBA families were ascertained and all 38 families were analyzed with additional polymorphic markers on chromosome 8p. In total, 18 of 38 families were consistent with linkage to chromosome 8p with a maximal LOD score with heterogeneity of 3.55 at D8S277 assuming 90% penetrance. The results indicate the existence of a second DBA gene in the 26.4-cM telomeric region of human chromosome 8p23.3-p22, most likely within an 8.1-cM interval flanked by D8S518 and D8S1825. Seven families were inconsistent with linkage to 8p or 19q and did not reveal mutations in the RPS19 gene, suggesting further genetic heterogeneity. (Blood. 2001;97:2145-2150)

Abstract

Pre-clinical studies in mice and haemophilic dogs have shown that introduction of an adeno-associated viral (AAV) vector encoding blood coagulation factor IX (FIX) into skeletal muscle results in sustained expression of F.IX at levels sufficient to correct the haemophilic phenotype. On the basis of these data and additional pre-clinical studies demonstrating an absence of vector-related toxicity, we initiated a clinical study of intramuscular injection of an AAV vector expressing human F.IX in adults with severe haemophilia B. The study has a dose-escalation design, and all patients have now been enrolled in the initial dose cohort (2 x 10(11) vg/kg). Assessment in the first three patients of safety and gene transfer and expression show no evidence of germline transmission of vector sequences or formation of inhibitory antibodies against F.IX. We found that the vector sequences are present in muscle by PCR and Southern-blot analyses of muscle biopsies and we demonstrated expression of F.IX by immunohistochemistry. We observed modest changes in clinical endpoints including circulating levels of F.IX and frequency of FIX protein infusion. The evidence of gene expression at low doses of vector suggests that dose calculations based on animal data may have overestimated the amount of vector required to achieve therapeutic levels in humans, and that the approach offers the possibility of converting severe haemophilia B to a milder form of the disease.

Abstract

To assess the safety and efficacy of a fixed dose of recombinant activated factor VII (rFVIIa; NovoSeven) in the home setting for mild to moderately severe joint, muscle; and mucocutaneous bleeding episodes in patients with haemophilia A or B with inhibitors.Multicentre, open-label, single arm, phase III study of one year duration. METHODS; Patients or their caregivers administered up to three doses of rFVIIa (90 microg/kg i.v.) at 3 h intervals within 8 h of the onset of a mild to moderate bleeding episode. Once the subject considered that rFVIIa had been "effective" with regard to haemostasis (after 1-3 injections), one further (maintenance) dose of rFVIIa was administered.Of 60 patients enrolled, 56 experienced at least one bleed, and 46 completed the one year study. 614 of 877 bleeds (70%) were evaluable according to protocol definitions. Haemostasis was rated as "effective" in 92% (566/614) of evaluable bleeds after a mean of 2.2 injections. For successfully treated episodes, the time from onset of bleeding until administration of the first injection was 1.1+/-2.0 h (mean+/-SD). Twenty-four hours after initial successful response, haemostasis was reported as having been maintained in 95% of cases. Efficacy was comparable for muscle, joint and target joint, and mucocutaneous bleeding episodes. In an intent-to-treat analysis of all 877 bleeding events, efficacy outcomes were equivalent to the evaluable bleeds, with an effective response in 88% of treated episodes. Treatment-related adverse events occurred in 32 (3% of all) bleeding episodes and consisted of re-bleeds/new bleeds in more than 50% (18/32) of these events. A single episode of superficial thrombophlebitis was the only thrombotic complication encountered, and there were no patient withdrawals due to adverse events. Development of FVII(a) antibodies could not be detected, and hypersensitivity reactions to rFVIIa were not reported.rFVIIa is effective and well tolerated when used in the home setting to treat mild to moderate bleeding episodes in patients with haemophilia A or B with inhibitors.

Abstract

The longitudinal changes in elbow and wrist motion for 48 patients with hemophilia were reviewed to determine the effect of recurrent hemarthroses. The average age of the patients at the time of followup was 23 years 9 months. The average duration of followup was 10.8 years. The patients were divided into 3 age groups: younger than age 15 years (14 patients), age 15 to 25 years (11 patients), and older than age 25 years (23 patients). For patients older than age 25 years, pronation, supination, elbow flexion and extension, wrist flexion and extension, and ulnar deviation were significantly decreased relative to patients younger than age 15 years. Pronation was the first motion to show a significant change, decreasing by 19% in patients age 15 to 25 years and by 31% in patients older than age 25 years. Loss of elbow extension showed the greatest change. In cases of severe hemophilic arthropathy of the elbow, synovectomy and radial head excision decreased elbow pain and bleeding episodes and improved supination and pronation.

Abstract

The overall laboratory features of the common RBC disorders occurring in Southeast Asians is summarized in Table 4. These erythrocyte disorders will continue to be important public health issues, and it has been predicted that most new cases of thalassemia in the United States will occur in this population group. The fertility rate in Southeast Asian families is very high, with an average of more than five children delivered by each married woman. This number of children is consistent with perceptions of ideal family size, and, to date, no evidence suggests any change in the size of Southeast Asian families who now reside in the United States. Moreover, attitudes about health care, reasons why one seeks medical attention, and a variety of other cultural issues may impair the effectiveness of genetic counseling and other preventive measures designed to reduce the incidence of serious blood diseases. Genetic screening and prenatal diagnosis clearly have led to a markedly decreased incidence of homozygous thalassemia disorders in high-risk Mediterranean populations throughout the world. With further assimilation into Western culture, a similar disease may occur in the Southeast Asian population also.

Abstract

Clinical studies evaluating highly purified monoclonal-antibody-derived and recombinant-DNA-derived clotting factor concentrates in previously untreated (PUPS) severe factor VIII (FVIII) deficient haemophilia patients, have documented an increased frequency of inhibitors compared with that seen in patients who have received less pure products. However, a valid comparison of inhibitor frequency in patients treated with pure and less pure products has not been possible because appropriate studies have not been done in PUPS treated with the less pure products. To determine the frequency of inhibitor development in PUPS treated solely with less pure plasma-derived products (specific activities < 5 FVIII U/mg protein), we reviewed the records of all haemophilia patients born between 1975 and 1985 and treated with such products at any of seven centres. 89 patients with severe FVIII deficiency (< 1%) were observed and tested for inhibitors from birth to 5 years old or until 30 bleeding episodes had been treated. 25 of the 89 patients developed inhibitors (28%), and 21 of these 25 were high-titre responders (> 5 Bethesda units). This frequency of inhibitor development is greater than that reported in patients treated with monoclonal FVIII products, but the latter patients may not have been followed as long as the patients in our report. Our data may make possible a meaningful comparison with the frequency of inhibitor development in PUPS treated solely with recombinant-DNA-derived FVIII.

Abstract

A case of Langerhans' cell histiocytosis confined to the mediastinum and presenting with de novo superior cava syndrome is reported. The causes of superior vena cava syndrome in childhood are discussed as is the importance of obtaining pathologic diagnosis prior to initiating therapy.

Abstract

Seventy-five patients who had hemophilia were followed clinically and roentgenographically to assess the prevalence of hemarthrosis and the prevalence and severity of arthropathy of the ankle. The mean age of the patients at the time of follow-up was twenty-two years and seven months. The patients were divided into four age-groups: less than ten years (eleven patients), ten to nineteen years (twenty-one patients), twenty to thirty years (twenty-four patients), and more than thirty years (nineteen patients). Intra-articular bleeding occurred more frequently in the joints of the lower extremities than in the joints of the upper extremities. During the second decade of life, hemarthroses occurred more often in the ankle than in the knee. A history of recurrent bleeding into the ankle joint, chronic synovitis, and overgrowth of the medial portion of the distal tibial epiphysis was associated with an early onset of arthropathy. In older patients, compression arthrodesis of the ankle joint was helpful in eliminating pain, recurrent bleeding, and equinus deformity.

Abstract

Congenital hypoplastic (Diamond-Blackfan) anemia is a rare macrocytic anemia, generally presenting during infancy or childhood. The condition usually occurs sporadically or in a pattern consistent with autosomal recessive inheritance, although autosomal dominant transmission has been proposed in some kindreds. We report the largest known kindred of congenital hypoplastic anemia, with at least 7 affected individuals over 3 generations, and propose that studies of this kindred may be useful for identifying the mechanism by which their genetic abnormality results in congenital hypoplastic anemia. Erythropoietic investigations on relatives show no inhibitors of erythropoiesis in serum, T-lymphocytes, or macrophages. Their erythroid progenitor cells (CFU-E and BFU-E) were generally quantitatively normal, and were capable of rapid proliferation, as judged by cell-cycle shortening. However, their erythroid progenitors displayed a relative insensitivity to recombinant erythropoietin, and produced relatively few normoblasts per erythroid progenitor cell. We propose that these and subsequent studies may be helpful in selecting candidate genes responsible for the molecular defect in this kindred.

Abstract

A new cell line, SUP-HD1, was established from the pleural effusion of a patient with nodular sclerosing Hodgkin's disease (NSHD). The SUP-HD1 cells had the characteristic morphology of Reed-Sternberg cells and contained acid phosphatase and nonspecific esterase. The cells lacked the Epstein-Barr virus (EBV) genome and reacted with monoclonal antibodies (MoAbs) against CD15 (Leu-M1), CD25 (Tac), CD71 (OKT9), Ki67, and HLA-Dr. However, the SUP-HD1 cells were nonreactive with MoAbs that specifically identify T lymphocytes, B lymphocytes, and macrophage/myeloid cells. Karyotype analysis of the cell line showed clonal abnormalities involving 1p13, 7p15, 8q22, and 11q23, chromosomal locations, at which breakpoints have been reported in HD. Southern blot analysis demonstrated rearrangement of the immunoglobulin heavy chain and kappa light chain genes as well as the gene for the beta chain of the T-cell receptor (TCR). Transcriptional analysis showed expression of RNAs for kappa light chain, interferon-gamma (IFN-gamma), and interleukin-2 receptor (IL-2R) but not IL-2. The SUP-HD1 cells lacked cytoplasmic and surface immunoglobulin heavy chain, but a small amount of cytoplasmic kappa light chain was detected. The presence of nuclear factor kappa B (NF kappa B), a B-lymphocyte-associated transcription factor, was demonstrated in stimulated and unstimulated cells. In addition, the SUP-HD1 cell line, produced IFN-gamma, a T-lymphocyte-associated lymphokine. Based on these data, the SUP-HD1 cells appear to be aberrant lymphocytes with characteristics of both activated B and T lymphocytes. Elaboration of lymphokines such as IFN-gamma by the malignant cells may represent one explanation for the unique clinical and pathologic features of HD.

Abstract

Loss of expression of a tumor-suppressing gene is an attractive model to explain the cytogenetic and epidemiologic features of cases of myelodysplasia and acute myelogenous leukemia (AML) associated with bone marrow monosomy 7 or partial deletion of the long arm (7q-). We used probes from within the breakpoint region on 7q-chromosomes (7q22-34) that detect restriction fragment length polymorphisms (RFLPs) to investigate three families in which two siblings developed myelodysplasia with monosomy 7. In the first family, probes from the proximal part of this region identified DNA derived from the same maternal chromosome in both leukemias. The RFLPs in these siblings diverged at the more distal J3.11 marker due to a mitotic recombination in one patient, a result that suggested a critical region on 7q proximal to probe J3.11. Detailed RFLP mapping of the implicated region was then performed in two additional unrelated pairs of affected siblings. In these families, DNA derived from different parental chromosome 7s was retained in the leukemic bone marrows of the siblings. We conclude that the familial predisposition to myelodysplasia is not located within a consistently deleted segment on the long arm of chromosome 7. These data provide evidence implicating multiple genetic events in the pathogenesis of myelodysplasia seen in association with bone marrow monosomy 7 or 7q-.

Abstract

The Philadelphia (Ph) chromosome translocation which is classically observed in chronic myeloid leukemia (CML) is sporadically found in acute lymphoblastic leukemia (ALL). In CML the translocation breakpoint on chromosome 22 is within the breakpoint cluster region, while in childhood ALL, no detectable change in breakpoint cluster region is routinely observed. In order to investigate the nature of this difference, we have established and characterized two cell lines from a child with Ph positive ALL. The cell lines have retained the cytochemical staining pattern, enzyme activity, monoclonal antibody profile, and immunoglobulin gene rearrangements of the child's malignant cells. The cell lines had the same Ph translocation t(9;22) (q34;q11) as the child's malignant cells along with additional chromosome changes. Southern blot analysis showed that the Ph translocation did not involve the 5.8-kilobase breakpoint cluster region segment characteristically seen in CML. The cell lines reported here will be a valuable resource in ascertaining the biological significance of the Ph translocation seen in ALL.

Abstract

In T cell malignancy, rearrangements of chromosome 14 have been observed with a break in the band that contains the alpha chain gene for the T cell receptor (TCR). Because the beta chain TCR gene is in chromosome band 7q34, we searched for and report finding specific rearrangements of 7q34 exclusively in T cell malignancies. The rearrangements were reciprocal translocations between 7q34 and other points: 1p34, 9q32, 9q34, 15q22, and 19p13. The malignancies containing a 7q34 translocation were either T cell acute lymphoblastic leukemias or T cell lymphoblastic lymphomas that had similarities in clinical, enzyme, immunologic, and cellular characteristics. Hybridization using a probe to the beta-TCR gene disclosed unique rearrangements consistent with clonality in every case. A common pattern with chromosome breakpoints involving TCR genes may be emerging in T cell neoplasia.

Abstract

Red-cell adenosine deaminase (ADA) activity in children with Diamond-Blackfan anaemia is significantly increased (1.91 +/- 0.90 U/g Hb) compared to that seen in transient erythroblastopenia of childhood (0.80 +/- 0.16 U/g Hb) or normal individuals (0.61 +/- 0.13 U/g). These data thus further support that measurement of this purine metabolic enzyme is useful in diagnosing the cause of pure RBC aplasia in children. Of interest, however, elevated RBC-ADA activity also is seen in some children with acute leukaemia and other haematologic disorders. In children with acute lymphoblastic leukaemia (ALL), the increase in RBC-ADA activity is proportional to the degree of anaemia. However, the elevated RBC-ADA activity in this leukaemic population is not related to the fetal haemoglobin concentration. These data suggest increased RBC-ADA activity may be a non-specific manifestation of abnormal erythroid stem cell function, an alteration distinct from that seen with reactivation of fetal erythropoiesis. However, since almost all patients with Diamond-Blackfan anaemia manifest elevated RBC-ADA activity, this chemical alteration yet may reflect the specific erythroid differentiation lesion in this disorder.

Abstract

The vast majority of pediatric RBC hypoplastic anemias are accounted for by red blood cell aplasia associated with chronic hemolysis, Diamond-Blackfan anemia, and transient erythroblastopenia of childhood. However, other causes of hypoplastic anemia occur in children, and some of these are similar to what is seen in adult RBC aplasia. For example, it has been reported that a 5-year-old girl with an aregenerative anemia had a thymoma and later developed pancytopenia. RBC aplasia also has been seen in children receiving anticonvulsant drug therapy, children recovering from severe protein malnutrition, children with hepatitis, and in children with leukemia during maintenance therapy. In addition, it is not uncommon for pediatric hematologists to observe children with RBC aplasia where there is no obvious diagnosis, although many are considered to be variants of Diamond-Blackfan anemia. Several important questions about RBC hypoplastic anemias in children need to be resolved; it is hoped that this will be accomplished in the next decade. Do RBC hypoplastic crises associated with hemolytic anemia occur with viral infections other than HPV? What is the cellular pathophysiology in DBA and TEC? Does the apparent heterogeneity of these disorders reflect limitations of laboratory techniques or are we looking at several different diseases? Is acute leukemia a real complication of Diamond-Blackfan anemia? Is TEC a completely benign entity or will we see other long-term problems in these children? Is the incidence of TEC actually increasing? Will TEC-like problems be seen in other aged children? As a case in point, we recently observed a 16-year-old girl who presented with pure RBC aplasia that required RBC transfusion support for 5 months; she also received prednisone therapy. After 7 months, however, this young lady had a spontaneous remission, and now 4 years later she is normal and free of any hematologic abnormalities. This was a most unusual event in our experience and, in view of the apparent increasing incidence of TEC in young children, we queried whether we were observing an adolescent equivalent of this disorder. During the next several years the answer to this and the other questions posed herein should be available.

Abstract

This paper describes the establishment and characterization of a new cell line (SUP-B7) which was established from a child with "common" acute lymphoblastic leukemia. The SUP-B7 cells (and the patient's tumor) have been characterized by cytochemical staining, monoclonal antibodies, enzyme analyses, gene rearrangement studies, and karyotype analysis. The SUP-B7 cells are periodic acid-Schiff positive, common acute lymphoblastic leukemia antigen positive, and terminal deoxynucleotidyl transferase positive, and they lack the Epstein-Barr virus genome. In addition, the SUP-B7 cells lack cytoplasmic and surface immunoglobulins, and the immunoglobulin gene rearrangement studies showed rearranged heavy chain genes with germ line light chain genes. Concordance between the cell line and the patient's tumor was established by the immunoglobulin gene rearrangement studies. Using Southern blot analysis of the DNA from the patient's tumor and the SUP-B7 cells, there was comigration of the bands representing the rearranged immunoglobulin heavy chain gene. In addition, the SUP-B7 cells possess a single chromosome abnormality: del(3)(q26q28), with the chromosome breakpoint at or near the transferrin receptor gene. Since the SUP-B7 cell line is concordant with the patient's malignancy and since these cells possess a single chromosomal abnormality, the SUP-B7 cell line may be a useful tool in determining the biological significance of the chromosome deletion: del(3)(q26q28).

Abstract

This case report describes a 16-year-old girl with pure red cell aplasia of 7 months duration. The erythrocyte characteristics and in vitro culture of erythroid progenitors was similar to that found in transient erythroblastopenia of childhood (TEC), a disorder most commonly seen in children 2 to 6 years of age. This case may represent the adolescent equivalent of TEC.

Abstract

Pyruvate kinase-(PK) deficient human reticulocytes incubated 4 hr under conditions where mitochondrial oxidative phosphorylation is inhibited become ATP-depleted. Concomitantly, these energy-depleted red blood cells (RBC) lose massive amounts of potassium and water. PK-deficient reticulocyte-rich RBC from a Basenji dog, incubated under the same conditions, also manifest ATP-depletion and K-loss. In contrast to the cation changes in human cells, however, K-loss in PK-deficient dog reticulocyte-rich RBC is balanced by an equivalent Na gain, and consequently these canine erythrocytes do not undergo any change in cellular hydration. Potassium depletion and dehydration, which may be related to membrane injury in human RBC, do not appear to be involved in the hemolysis of PK-deficient dog erythrocytes.

Abstract

Children with acute leukemia in remission manifest reticulocytosis and a significant increase in hemoglobin concentration (mean increment of 2.3 +/- 1.1 g/dl) following prednisone pulse therapy. This hemoglobin increment is not associated with changes in serum erythropoietin activity. It is speculated that this stimulation of red cell production may be a direct effect of steroids on erythroid progenitor cells.

Abstract

It previously has been reported that red blood cells (RBC) of patients with Diamond-Blackfan syndrome (DBS) have increased activity of orotidine decarboxylase (ODC) and adenosine deaminase (ADA). The studies reported here compared the activity of these two enzymes in DBS erythrocytes, cord blood, and reticulocytes. The activity of ODC, although increased in some DBS erythrocytes, was not significantly different from that seen in cord RBC or reticulocytes. In contrast, RBC-ADA activity was increased in 23 of 26 DBS patients; and this enzyme elevation was distinct from that seen in cord blood and reticulocytes. Moreover, ADA activity was normal in 26 of 27 patients with transient erythroblastopenia of childhood (TEC). Taken together, these data indicate RBC-ADA activity is more sensitive than ODC as a marker of DBS. In addition, RBC-ADA activity continues to be useful for distinguishing DBS and TEC in most patients with RBC hypoplasia.

Abstract

A 17-year-old previously healthy girl is reported who developed acute infectious mononucleosis followed by progressive ill health over 20 months, associated with pancytopenia and a polyclonal B-lymphoproliferation, terminating in acute lymphoblastic leukemia (ALL). Epstein-Barr virus (EBV) was recovered from the patient's nasopharyngeal secretions; serologic titers of antibodies to EBV-associated antigens were compatible with a chronic persistent EBV infection. Plasma interferon levels were markedly elevated. EBV-specific cell-mediated immunity, as well as Natural killer (NK) cell activity were markedly deficient. Other studies of cell-mediated immunity revealed notable abnormalities, including abnormalities in T-cell subset ratios, and a serum blocker of autologous mitogen-induced lymphoproliferation. Humoral (plasma)-mediated, but not cell-mediated, suppression of hemopoiesis was demonstrated using in vitro erythroid and myeloid colony culture techniques. Immunophenotyping of the patient's bone marrow cells preterminally was consistent with ALL. Autopsy revealed pathologic changes of ALL in marrow and multiple organs. We conclude that our patient developed an EBV-driven lymphoproliferative disorder, with associated defective cell-mediated immunity and hemopoiesis. Ultimately, the patient's documented polyclonal lymphoproliferative state was superimposed by acute lymphoblastic leukemia.

Abstract

It has been suggested that the less severe anemia that exists in patients with sickle cell anemia who also have alpha-thalassemia is related to an effect on the sickling of erythrocytes. To test this hypothesis, we used as a measure of sickling the change in sickle erythrocyte sodium and potassium content that occurs during deoxygenation. Sickle cells from individuals with four, three, or two alpha-globin genes were deoxygenated, and the change in monovalent cation content measured to determine whether a relationship exists between alpha-globin gene number and sickling. In samples of cells depleted of irreversibly sickled cells, the alpha-globin gene number was directly related to the magnitude of mean cation change and inversely related to the ratio of membrane surface area to cell volume. These data indicate that alpha-thalassemia is associated with a diminished degree of sickling in individuals with sickle cell anemia. They also suggest that excess cell membrane may play a role in this protective effect.

Abstract

A fatal myocardial infarction in a 22-year-old man with hemophilia A and a factor VIII inhibitor is described. The catastrophic event occurred while the patient was receiving high doses of unactivated prothrombin complex concentrates. Autopsy examination revealed myocardial hemorrhage with no evidence of coronary artery disease or thrombosis. There also was postmortem evidence of previous myocardial infarctions. This is the fourth documented case of myocardial infarction occurring in a young hemophiliac patient using unactivated prothrombin complex concentrates. It is concluded that utilization of prothrombin complex concentrates in hemophiliac patients must be limited and closely monitored. Therapeutic guidelines are recommended.

Abstract

Recently, four distinct cell lines were established from patients whose malignancies had been defined by immunological and biochemical markers. Each patient had a distinct subtype of a T-cell cancer, and each possessed elevated adenosine deaminase and reduced nucleoside phosphorylase activity. Cell lines cultured in vitro possessed the same basic immunophenotype and biochemical enzyme activity as the patients' original malignant cells. In a direct comparison of the immunophenotype of the cell lines and the patients' malignant cells, full concordance existed for 48 of 52 paired antibody tests performed. However, when compared to the corresponding patient's sample, each cell line showed some minor changes in antigen expression or enzyme level. Antigen loss, de novo antigen expression, or elevated adenosine deaminase levels occurred in the cell lines, and these changes were stable on repeated analysis. While there was good general concordance between the patient's cancer and the established cell line, minor biological differences in the cell lines may reflect cellular maturation or subpopulation selection in vitro.

Abstract

Two children with Ewing's sarcoma developed acute nonlymphocytic leukemia (ANLL) during the course of their illness. One patient developed ANLL after apparently successful treatment of his primary malignancy with radiation therapy and multiagent chemotherapy. In the second patient, acute leukemia developed before the administration of radiotherapy or systemic chemotherapy. The development of secondary ANLL after Ewing's sarcoma has been reported only twice previously, most likely representing a therapy-induced complication. The occurrence of ANLL in Patient 2 prior to therapy suggests that these two disorders may have a more than treatment-related association. Close follow-up of long-term survivors of Ewing's sarcoma with surveillance for secondary acute leukemia is advised.

Abstract

Active transport of Na and K under physiologic and maximally stressed conditions was identical in normal adult red blood cells (RBC) and term neonatal erythrocytes. These results are consistent with the previous observation that Na-K ATPase is the same in normal adult RBC and term neonatal erythrocytes. These data, however, are at variance with a previous observation that active K transport is impaired in neonatal erythrocytes. The most reasonable explanation for this difference relates to inherent problems with the use of radioisotopes which were used in previous in vitro studies of cation transport.

Abstract

Abnormalities of adenosine deaminase, a critical enzyme of the purine salvage pathway, have been reported in association with immune dysfunction, acute leukemia, and hereditary hemolytic anemia. We report data showing that erythrocyte adenosine deaminase activity is also abnormal in congenital hypoplastic anemia (the Diamond-Blackfan syndrome). Adenosine deaminase activity in erythrocytes from 12 patients (mean +/- S.D., 2.20 +/- 0.77 IU per gram of hemoglobin) was substantially greater than that observed in 50 controls (0.62 +/- 0.13 IU per gram). Enzyme activity in affected patients was also greater than that seen in cord blood or in erythrocytes from patients with hemolytic anemia, acquired aplastic anemia, Fanconi's hypoplastic anemia, acquired pure red-cell aplasia, or transient erythroblastopenia of childhood. These observations indicate that erythrocyte adenosine deaminase activity may be a unique marker for identifying congenital hypoplastic anemia.

Abstract

Platelet-associated IgG was studied in children with acute and chronic ITP and in patients with thrombocytopenic SLE, using the microtiter solid-phase radioimmunoassay. Of the children with acute ITP, 85% had elevated PAIgG levels. The degree of elevation of PAIgG at onset of disease did not correlate with the development of chronicity. Of the children with acute ITP, clinically and hematologically indistinguishable from the rest, 15% had normal PAIgG values. All of 22 children with chronic ITP had elevated PAIgG values. Although there was good correlation between the platelet count and the PAIgG value in children with chronic ITP, the association was not as striking in those with acute ITP; thus, factors in addition to the level of PAIgG may contribute to the thrombocytopenia in the latter group. Patients with SLE and thrombocytopenia had higher values of PAIgG than would be predicted from the platelet count; the PAIgG value is probably not the only factor determining the degree of immune thrombocytopenia.

Abstract

During the past several years, there has been much emphasis on understanding the relationship between abnormalities in RBC metabolism and hereditary haemolytic anaemias. More recently, attention has focused on utilizing erythrocyte biochemical abnormalities in the diagnosis of systemic disorders not necessarily associated with altered RBC function. In this chapter, we have enumerated several non-erythrocytic clinical conditions clearly associated with altered RBC metabolic products or enzyme activity. Specifically, we have described the use of erythrocytes (1) to diagnose inborn errors of metabolism, (2) to assess many nutritional disorders, (3) to monitor hyperglycaemia in patients with diabetes mellitus, and (4) to discriminate between essential and non-essential hypertension. As Eric Ponder said many years ago (Ponder, 1948), 'I have been told that I tend to speak of the red cell as if it were a microcosm, as if an understanding of its nature and properties would include an understanding of nearly everything else in the cellular world. To some extent this is true.' When the list of conditions for which the red cell can be used as a biopsy tool is reassessed several years from now, most assuredly many new clinical conditions will be added to the diseases we have discussed. For example, our knowledge of normal membrane structure and function currently is in its infancy, yet it already appears that analysis of RBC membranes may be useful in detecting certain neurological disorders such as muscular dystrophy (Roses, Herbstreith and Appel, 1975). Needless to say, to the delight of Dr Eric Ponder, the utility of the erythrocyte as an investigative tool appears to be without limit.

Abstract

Erythrocyte metabolic abnormalities should be considered as a possible cause of hemolysis when there is no evidence of an immune-mediated hemolytic anemia, no consumptive red blood cell disorder, no morophologic or laboratory data to suggest a problem of the red cell membrane, and no evidence of a quantitative or qualitative defect in hemoglobin synthesis. Glucose-6-phosphate dehydrogenase deficiency is clearly the most common enzyme deficiency causing clinical problems.

Abstract

RBC K loss and cellular dehydration are associated with a variety of normal and abnormal erythrocyte conditions. In some cases (normal RBC aging, pyruvate-kinase-deficient RBCs and irreversibly sickled cells) cation and water changes are related to adenosine triphosphate (ATP) depletion and to increased RBC calcium content. In other disorders, such as hereditary xerocytosis, cation depletion and cellular hydration are not related to altered energy or calcium metabolism. Rather, this condition is thought to be due to a structural membrane defect which is manifested by imbalanced cation leaks (K less greater than Na gain) for which the active cation transport is unable to compensate. None of the disorders described here are associated with known structural membrane alterations. The fact that K loss and cellular dehydration are common to several RBC disorders suggests that this phenomenon may have a direct role in membrane injury. This hypothesis is supported by two separate observations: 1)Formation of irreversible sickled cells in vitro is prevented if K and water loss are inhibited, and these effects are independent of ATP depletion and calcium accumulation; 2) the mean critical hemolytic volume is markedly reduced in K- and water-depleted normal RBCs. RBC dehydration without intracellular cation depletion, however, is not associated with changes in mean critical hemolytic volume. These data thus indicate that K loss may have a direct role in RBC membrane injury. The mechanism by which this occurs and the associated alterations in membrane structure, however, remain to be identified.

Abstract

Total and differential WBC counts were measured in 88 children with sickle cell hemoglobinopathies during the steady state, vaso-occlusive crisis, and bacterial infection. Steady state leukocyte values were lower than anticipated on the basis of currently available information. Total and segmented leukocyte numbers were greatly increased during vaso-occlusive crisis and infection, but only with bacterial infection was there a consistent increase in bands or nonsegmented leukocytes (mean, 4,580/microliter). On the basis of these data we believe that total and differential leukocyte counts are of value for identifying those children with potentially serious bacterial infections.

Abstract

In order to assess how the number of cell divisions influences the red blood cell (RBC) content of proteins other than hemoglobin, we measured the activity of two age-independent glycolytic enzymes in macrocytic, normal, and microcytic RBCs. The enzymes measured were phosphoglycerate kinase (PGK) and lactic dehydrogenase (LDH). In macrocytes, both PGK and LDH activity/10(10) RBCs were increased 1.6-fold over normal RBCs. In microcytes, however, the activity of these enzymes was identical to that seen in normal RBCs.

Abstract

Cation composition, cellular hydration, and adenosinetriphosphate (ATP) content were measured in irreversible sickle cells (ISC's) separated from the blood of patients with sickle cell anaemia. Total monovalent cation (Na+ + K+) content was markedly reduced in ISC's and this largely was due to cell K+ depletion. Corresponding to the reduced cation content, cells were dehydrated as indicated by a reduced mean cell volume. ISC's also appeared to be grossly depleted of ATP. These biochemical characteristics allow us to expand the definition of ISC's beyond morphologic characteristics. In addition, these chemical alterations provide a means for elucidating the mechanism of ISC production in vitro.

Abstract

Sickle erythrocytes (RBC) incubated under 100% nitrogen for 4 hr manifested marked Na gain with an equivalent K loss. There were no changes in cell total cation or water content under these conditions, and no irreversible sickle cells (ISC) were formed. In contrast, sickle RBC incubated for 24 hr under 100% nitrogen in a glucose-free Na medium containing calcium manifested marked ISC formation. ISC formed under these conditions also had elevated Na content, although K content was much more reduced, and consequently ISC were cation depleted and dehydrated. When sickle RBC were incubated 24 hr under 100% nitrogen in a glucose-free K medium containing calcium no ISC formed and there were no major changes in cation or water content. These studies indicate that the Na+K content and dehydration of ISC was not directly related to the increased cation permeability associated with sickling. Rather, the ISC changes appear to reflect the well-known Gardos effect (K and water loss occurring in ATP-depleted RBC incubated with calcium). In addition, these studies suggest that ISC formation per se is related to K and water loss, since no ISC were formed when ATP-depleted sickle RBC were deoxygenated in calcium-containing high-K media that prevented K loss and dehydration.

Abstract

Propranolol, in the presence of calcium, causes marked K efflux from human red blood cells (high K, low Na). The studies reported here indicate this effect of propranolol is specific for K and does not represent a nonspecific permeability increase for intracellular cations to leave the cell. Amphotericin-treated human RBC's (high Na, low K) and dog RBC's (high Na, low K) both gain K and increase in size when incubated in a K-medium containing propranolol and calcium. No effect was noted when cat RBC's (high Na, low K) were similarly treated. Propranolol, independent of added calcium, also inhibited the normally increased Na efflux observed when dog RBC's are suspended in K-medium. These species differences in response to propranolol thus may serve as a focus for elucidating the mechanism by which this drug alters normal membrane physiology. The unique drug effect on Na permeability of canine erythrocytes also may be a useful probe for the study of dog RBC volume regulation.

Abstract

Since the approach to the management and outcome of extreme hyperbilirubinemia in patients with sickle cell anemia is not clearly defined, we reviewed our experience with marked hyperbilirubinemia in six children with sickle cell disease. Intrahepatic sickling (sickle hepatopathy) rather than hepatitis or biliary stones appeared primarily responsible for the extreme jaundice in at least four children and possibly in all six. Signs and symptoms were few, and laboratory abnormalities were not striking other than marked hyperbilirubinemia (total serum bilirubin concentrations ranging from 20.4 to 57.6 mg/dl with approximately one half conjugated). All of the children improved within days to weeks and currently are well, without recurrence of hyperbilirubinemia or evidence of chronic liver disease. The patients described here suggest that sickling within the liver, previously reported to be a serious and even fatal syndrome, usually is a benign and self-limited process.

Abstract

Serious bleeding episodes in newborn infants can usually be diagnosed following careful clinical assessment and a few simple laboratory tests. Certain conditions are found almost exclusively in "sick" infants, whereas other coagulation abnormalities occur in otherwise "healthy" neonates. Successful management of hemorrhage necessitates a correct diagnosis which thereby dictates appropirate therapy. In some cases, such as in DIC, successful outcome ultimately depends on correction of the underlying pathophysiology which triggered the coagulation disturbance.

Abstract

Salicylate is known to uncouple mitochondrial oxidative phosphorylation. Since the viability of pyruvate-kinase-deficient reticulocytes depends on ATP generated by mitochondrial metabolism, this study examined the effects of salicylate on erythrocytes deficient in pyruvate kinase. When deficient erythrocytes from patients with severe hemolysis were incubated with salicylate (2 to 30 mg per deciliter), there was a marked decrease (25 to 75 percent) in ATP. In addition, this drug-induced ATP depletion produced cell potassium and water loss, and the normal oxidant responsiveness of the hexose-monophosphate shunt was blunted. Since these cellular abnormalities are associated with accelerated hemolysis in vivo, the data suggest that aspirin therapy may aggravate hemolysis in patients with pyruvate kinase deficiency whose erythrocyte manifest sensitivity to salicylate in vitro.

Abstract

Three models of disturbed erythrocyte metabolism, triose-depleted normal, phosphoglycerate kinase (PGK)-deficient, and pyruvate kinase (PK)-deficient cells, have been studied to examine further the role of PGK in erythrocyte cation transport. Sodium (Na-+) and potassium (K-+) transport were reduced only in cells fully depleted of triose. In such cells the PGK step presumably was inoperative due to total lack of substrate; 2,3-diphosphoglycerate (2,3-DPG) then became the sole substrate source for remaining steps in glycolysis. At increased intracellular Na-+ concentrations which normally stimulate transport and glycolysis, triose-depleted cells had marked impairment of cation transport and ouabain-inhibitable lactate and pyruvate production from 2,3-DPG. PGK-deficient cells and normal cells with high intracellular Na-+ concentrations had similar increases in transport and ouabain-inhibitable lactate production. PK-deficient cells with high intracellular Na-+ concentrations showed an appropriate increase in transport but less stimulation of lactate production. Transport was not related to total cellular adenosine triphosphate (ATP) concentration. These data suggested that normal coupled cation transport occurred despite diminished metabolite flow through PGK, as in PGK- or PK-deficient cells. Transport was diminished only in triose-depleted cells where metabolite flow through PGK was presumably absent. These data, therefore, support the concept that transport and glycolysis interact at the PGK step, although impairment of PGK must be profound before its effect on transport is evident.

Abstract

To determine the hepatic and intestinal toxicity of sodium cyanate, this compound was administered to rats by orogastric tube (PO) or intraperitoneal injection (IP). At low dosage (50 mg. per kilogram per day PO for 8 weeks), the animals showed no clinical effects other than mild lethargy. They had normal intestinal absorption studies, but demonstrated decreased liver G6PD activity and a slight increase in hepatic glycogen. At higher dose levels (200 mg. per kilogram per day PO for 10 days, 400 mg. per kilogram per day PO for 3 days, and 100 mg. per kilogram per day IP for 10 days), the animals became very lethargic and developed hind-limb paralysis; many animals died during the period of dosing. The severity and rate of onset of symptoms increased proportionally with the dose level. Liver sections from rats receiving these higher doses showed striking increases in glycogen deposition. Activities of hepatic enzymes involved in glycogen synthesis and degradation were measured in rats receiving 200 mg. per kilogram per day PO or 100 mg. per kilogram per day IP. Significant decreases were noted in the activities of glucose-6-phosphatase and G6PD in PO-dosed rats. The activities of phosphorylase, UDPG-pyrophosphorylase, glycogen synthetase, phosphoglucomutase, and debrancher did not differ from control rats. In IP-dosed rats, significant decreases were observed in the activities of glucose-6-phosphatase, G6PD, phosphorylase, and UDPG-pyrophosphorylase, but not in the other glycogen-related enzymes. Our data suggest that sodium cyanate affects several enzymes of hepatic glycogen metabolism but that the enzymes vary in their susceptibility (glucose-6-phosphatase and G6PD greater than phosphorylase and UDPG pyrophosphorylase.

ROLE OF ELEVATED GLUCOSE CONCENTRATIONS IN HEMOLYSIS OF GLUCOSE-6-PHOSPHATE-DEHYDROGENASE DEFICIENT ERYTHROCYTESPROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINEGlader, B. E.1975; 148 (1): 50-53